


The Serial Killer's Killer

by HollyKasakabe



Series: Tumblr Requests [2]
Category: Sherlock (TV)
Genre: 1.5k, 2nd POV, 2nd Person, Gen, HollyKasakabe, Other, Reader-Insert, Scotland Yard, Tumblr request, open-ended
Language: English
Status: Completed
Published: 2017-02-19
Updated: 2017-02-19
Packaged: 2018-09-25 15:59:36
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,601
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/9827690
Author URL: https://archiveofourown.org/users/HollyKasakabe/pseuds/HollyKasakabe
Summary: Request: I would like to take a second to say good luck with this! Also, may I have a ff of a Sherlock x reader thing where the reader is a serial killer (who kinda kills like Dexter—only takes out the bad people). Sherlock being Sherlock is highly intrigued by the case and is amazed at how well though out the killings are and is kinda a fan of their intelligence and when they meet, the reader is happy to meet him or something? (I know this is a mess and weird but I just wanted to see where it would go)





	

**Author's Note:**

> Y/N - Your Name

A serial killer was plaguing London. New Scotland Yard was on alert, parents were instating earlier curfews, college students and young adults were taking care to stick together, and security was being increased in public venues. With the body count only rising, no one had any strong leads on who was behind the murders, and John Watson's blog entries were only getting longer and longer.

Sherlock Holmes was only getting easier and easier to live with – quietly retracting into his Mind Palace, being kind and patient with Mrs. Hudson, and leaving John alone to go on his dates with Quinn, a pretty woman who had brought her little girl in to the surgery after she took a bad fall and broke her wrist. He stuck a few nicotine patches on his arm and acted like a statue on the couch or he picked up his violin and played. The one time he didn't let John take care of his own interests was when there was a crime scene… which there was.

A London alleyway was cordoned off by Lestrade and Donovan. Anderson was running point on forensics. An intern working for the Yard was working underneath Lestrade and so they were there, too. Y/N was a clever one who set Donovan off, but Lestrade liked that Y/N was sharp-minded and seemed unshakeable, even in front of dead bodies.

"Oh, hello, Dr. Watson," Y/N greeted as Sherlock bounded right past them, heading right to the body and bypassing Lestrade in the process. John followed, looking tired of being herded to the crime scenes by his flatmate.

"Ah, morning, Y/N." John rubbed his eyes and forced a smile. Y/N hovered near John while Sherlock observed the body, crowding Anderson away while the latter nagged at him about the forensic integrity. Anderson always seemed to have it out for the consulting detective. Y/N would have had it out for Anderson, except for that that was obvious.

"We don't have an ID on him yet," Lestrade told Sherlock. Sherlock appeared not to be listening, but everyone knew better. "Middle-aged white man, married-"

"How do you figure?" Sherlock looked up, his hair flopping over his forehead.

"Well, there's a ring," Lestrade pointed out.

Sherlock frowned at Lestrade. " _Engagement_ ring, Lestrade. This man has been engaged for less than a week. There isn't even a tan line underneath the ring."

"Maybe it was a shotgun wedding," Y/N suggested halfheartedly. Y/N liked to work with the police, even though interns weren't paid. The one thing was that they had to be careful not to bring too much attention to themselves. They didn't want to be caught because they stood out.

The fact was that Y/N knew exactly who the victim was, and they also knew who had killed him – because Y/N was the murderer. They didn't feel very badly about it. The man had had it coming. This was going to be the last in the rash of murders from the vicious serial killer Scotland Yard had been chasing. Y/N knew that to be true because the man lying prone mere inches from Sherlock's shoes was the murderer himself.

Sherlock called himself a high-functioning sociopath. Y/N had been diagnosed. Not all sociopaths were violent, yet Y/N was. They were just very controlled. Y/N had no interest whatsoever in being imprisoned and they quite liked their comfortable life, so they were careful not to be caught. It had started with a friend dying when they were nine. From then on, Y/N had an obsession with death that had sent her to psychotherapists until they turned eighteen. Y/N hadn't been able to hide it from everyone, but her therapist had majored in her profession thanks to her younger brother being compulsively violent. She trained Y/N to control their urges and release them on the people who deserved it.

Y/N figured that a serial killer deserved a taste of their own medicine.

"The bruises reached peak lividity before rigor mortis set in." Anderson, in a puffy white crime scene suit that made him look like a short, angry marshmallow, crossed his arms and sulked beside Donovan. Y/N thought it was rude to cheat on his wife, but, again, Anderson could be connected to her. They worked together. "Just like the others, there's-"

"Syndactyly," Sherlock interrupted archly, unwilling to let Anderson have the spotlight.

"Syndactyly?" Y/N asked John, feigning confusion.

"Uh, it's when fingers are fused together." John explained briefly and held up a hand, keeping his index and middle fingers together. Y/N nodded in understanding while internally they hid a grin. They hadn't been sure that the bruise would take like it was supposed to and was delighted that it had.

Sherlock turned the wrist of the corpse over so the palm was facing the ceiling. He peered down and analyzed the hand. Y/N bit the inside of their cheek.

"Syndactyly on the victim, as well," he announced, rocking back onto his heels thoughtfully while he crouched down. He went off somewhere else mentally despite remaining right where he was.

"Coincidence?" Lestrade assumed. When Sherlock gave him a disappointed stare, Lestrade defended, "Well, it's not like he bruised himself, did he?"

"As usual, Gary, you've seen the obvious solution to your own case and proceeded to rush past." Sherlock whipped his coat around as he stood up, losing interest in the corpse. Y/N wondered what else he had seen that he had refrained from announcing. Stalking off, he left Lestrade standing there, bemused and affronted.

"It's _Greg,"_ he corrected loudly after Sherlock, who brushed past John, who waved a little goodbye at Y/N and followed his flatmate.

* * *

Come the next morning, Y/N was at work early and was doing the normal internship things, such as organizing file cabinets and taking phone calls when they came in.

"Uh-huh. Yes, sir." Y/N just wanted to get off of the phone. The caller didn't seem to realize that they weren't the person to be pissed at. They wanted to transfer the call, but the caller just wasn't having that. Instead, Y/N listened with half an ear and doodled geometric shapes on a post-it note on the desk. "Yep. Thanks." Losing patience, Y/N cut them off and hung up the phone as they were coming to the end of their spiel.

They looked up, sighing with irritation, and came face-to-face with Sherlock Holmes leaning over the front of the desk, smiling uncharacteristically. He leaned an arm over the front and was actively trying to keep from showing his teeth as he smiled, the same sort of expression someone used when they were trying not to giggle. Y/N leaned back. It was normal for Sherlock to come to them about Lestrade's whereabouts, but not for him to look happy.

"Morning," Y/N told him with wide eyes. "Lestrade's not in yet."

"I'm not here for Lestrade." His grin widened, his lips pulling up and eyes intense. "Tell me, Y/N, how long have you been doing it?"

Y/N had been so careful, but couldn't think of anything but their homicidal pastimes that might bring Sherlock such excitement to confront them about. Heart in their throat, Y/N blinked. "Doing what?"

Sherlock looked to both sides and then bent further over the desk, isolating the conversation between the two of them. Y/N was grateful for that, especially if their fear was true. "Yesterday's victim, staged as another victim of the same killer Lestrade has been after, was actually the suspect. The syndactyly wasn't a coincidence. It was staged on him to fit the signature bruises on the other bodies. Clever move, throwing off the police," he complimented before sobering to grave solemnity. "Thing is, that was never released to the public. Once I knew the victim was the original killer, it was only to be concluded that the new murderer was within the Yard."

Y/N swallowed. If they hadn't included the anomaly to the fingerprint bruises, then there wouldn't have been the signature to convince Lestrade that it was the same culprit. Y/N had hoped Sherlock wouldn't know that aspect when he was usually careless about police documents.

"How did you know it was me?" They whispered. "There are so many people here who could read the reports, too."

Sherlock looked at them as if they were missing something obvious. Y/N understood – they didn't need a precise answer because he was Sherlock Holmes. He could deduce anything from the smallest aspects of any given something. Y/N had been safe when he didn't know to be alert, but now that he was on the path, they weren't secure.

"Truly, it is remarkable that you've evaded capture this long." Part of Y/N was pleased that she was being praised by someone as clever and egotistical as Sherlock. Another part was just anxious of what would happen next. Yet… come on. Sherlock Holmes had never acted like this much of a fan of someone else's work. That had to be an honor of the highest order for any criminal of any kind. "Even more so that the reason no one has been looking for you is that they aren't aware you exist."

"Are you going to turn me in?" Y/N blurted, unable to hold their tongue any longer, looking around. They were in the middle of New Scotland Yard, surrounded by officers who could come running as soon as the alarm was raised…


End file.
